Return and pass around clock skew to be used in latency calculations.

Closes #1920

webroot/js/app.js

@@ -319,8 +319,12 @@ export default class App extends Component {
       lastConnectTime,
       streamTitle,
       lastDisconnectTime,
+      serverTime,
     } = status;
 
+    const clockSkew = new Date(serverTime).getTime() - Date.now();
+    this.player.setClockSkew(clockSkew);
+
     this.setState({
       viewerCount,
       lastConnectTime,